This solicitation of proxies is made by the board of directors of United Security Bancshares. The expense of preparing, assembling, printing and
mailing this proxy statement and the materials used in the solicitation of proxies for the meeting will be borne by United Security Bancshares. It is contemplated that proxies will be solicited principally through the use of the mail, but
directors, officers and employees of United Security Bancshares may solicit proxies personally or by telephone, without receiving special compensation.

This solicitation of proxies is made by the board of directors of United Security Bancshares. The expense of preparing, assembling, printing and mailing this
proxy statement and the materials used in the solicitation of proxies for the meeting will be borne by United Security Bancshares. It is contemplated that proxies will be solicited principally through
the use of the mail, but directors, officers and employees of United Security Bancshares may solicit proxies personally or by telephone, without receiving special compensation.

Voting Securities

There were issued and outstanding 11,833,566 shares of United Security Bancshares' common stock on
March 28, 2008, which has been fixed as the record date for the purpose of determining shareholders entitled to notice of, and to vote at, the meeting. On any matter submitted to the vote of
the shareholders, each holder of United Security Bancshares' common stock will be entitled to one vote, in person or by proxy, for each share of common stock he or she held of record on the books of
United Security Bancshares as of the record date. In connection with the election of directors, shares may be voted cumulatively if a shareholder present at the meeting gives notice at the meeting,
prior to the voting for election of directors, of his or her intention to vote cumulatively. If any shareholder of

1

United
Security Bancshares gives such notice, then all shareholders eligible to vote will be entitled to cumulate their shares in voting for election of directors. Cumulative voting allows a
shareholder to cast a number of votes equal to the number of shares held in his or her name as of the record date, multiplied by the number of directors to be elected. These votes may be cast for any
one nominee, or may be distributed among as many nominees as the shareholder sees fit. If cumulative voting is declared at the meeting, votes represented by proxies delivered pursuant to this proxy
statement may be cumulated in the discretion of the proxyholders, in accordance with management's recommendation. The effect of broker non-votes is that such votes are not counted as being
voted; however such votes are counted for purposes of determining a quorum. The effect of a vote of abstention on any matter is that such vote is not counted as a vote for or against the matter, but
is counted as an abstention.

Shareholdings of Certain

Beneficial Owners and Management

Management of United Security Bancshares knows of no person who owns, beneficially or of record, either individually or together with associates, five percent
(5%) or more of the outstanding shares of United Security Bancshares' common stock, except as set forth in the table below. The following table sets forth, as of March 15, 2008, the number and
percentage of shares of United Security Bancshares' outstanding common stock beneficially owned, directly or indirectly, by each of United Security Bancshares' directors, named executive officers and
principal shareholders and by the directors and executive officers of United Security Bancshares as a group. The shares "beneficially owned" are determined under Securities and Exchange Commission
Rules, and do not necessarily indicate ownership for any other purpose. In general, beneficial ownership includes shares over which the director, named executive officer or principal shareholder has
sole or shared voting or investment power and shares which such person has the right to acquire within 60 days of March 15, 2008. Unless otherwise indicated, the persons listed below
have sole voting and investment powers of the shares beneficially owned. Management is not aware of any arrangements that may, at a subsequent date, result in a change of control of United Security
Bancshares.

Beneficial Owner

Amount and Nature of Beneficial Ownership

Percent of Class(1)

Directors and Named Executive Officers:

Robert G. Bitter, Pharm. D.

225,219

(2)

1.9

Rhodlee A. Braa

210,922

(3)

1.8

Stanley J. Cavalla

573,373

(4)

4.5

Kenneth L. Donahue

277,950

(5)

2.4

Tom Ellithorpe

194,770

(6)

1.7

David L. Eytcheson

170,313

(7)

1.4

R. Todd Henry

49,200

(8)

*

Gary Hong

10,914

*

Ronnie D. Miller

174,283

(9)

1.5

Robert M. Mochizuki

73,164

(10)

*

Walter Reinhard

503,309

4.3

William F. Scarborough

25,470

(11)

*

John Terzian

191,251

(12)

1.6

Dennis R. Woods

803,430

(13)

6.8

Michael T. Woolf, D. D. S.

13,659

*

All Directors and Executive Officers as a Group
(15 in all)

3,461,227

29.1

Principal Shareholder

Audry "Bobbi" Thomason

781,469

(14)

6.5

*

Less
than one percent (1%).

2

(1)

Includes
shares subject to options held by the directors and executive officers that were exercisable within 60 days of March 15, 2008. These are treated as issued and
outstanding for the purpose of computing the percentage of each director, named executive officer and the directors and executive officers as a group, but not for the purpose of computing the
percentage of class owned by any other person.

(2)

Dr. Bitter
has shared voting powers as to powers as to 145,403 of these shares and shared investment powers as to 39,762 of these shares.

(3)

Mr. Braa
has shared voting and investment powers as to 46,042.

(4)

Mr. Cavalla
has shared voting and investment powers as to 366,173 of these shares.

(5)

Mr. Donahue
has shared voting and investment powers as to 275,833 of these shares.

(6)

Mr. Ellithorpe
has shared voting and investment powers as to 84,098 shares.

(7)

Mr. Eytcheson
has shared voting and investment powers as to 170,313 of these shares.

(8)

Mr. Henry
has 6,000 shares acquirable by exercise of stock options.

(9)

Mr. Miller
has shared voting and investment powers as to 153,338 of these shares.

(10)

Mr. Mochizuki
has shares voting and investment powers as to 65,164 shares and 8,000 shares acquirable by exercise of stock options.

(11)

Mr. Scarborough
has shares voting and investment powers as to 1,420 shares and 24,000 shares acquirable by exercise of stock options

(12)

Mr. Terzian
has shared voting and investment powers as to 82,640 of these shares. Mr. Terzian disclaims ownership of 2,400 shares that he has beneficial ownership as a
custodian for minors.

(13)

Mr. Woods
has shared voting and investment powers as to 684,993 of these shares, and has 20,000 shares acquirable by exercise of stock options. Mr. Woods disclaims
ownership of 18,916 shares that he has beneficial ownership as a custodian for minors. Mr. Woods' address is c/o United Security Bancshares, 2126 Inyo Street, Fresno, California 93721.

This solicitation of proxies is made by the board of
directors of United Security Bancshares.
The expense of preparing, assembling, printing and mailing this proxy
statement and the materials used in the solicitation of proxies for the meeting
will be borne by United Security Bancshares.
It is contemplated that proxies will be solicited principally through
the use of the mail, but directors, officers and employees of United Security
Bancshares may solicit proxies personally or by telephone, without receiving
special compensation.

This solicitation of proxies is being made by the board of directors of
United Security Bancshares. The expense of preparing, assembling, printing and
mailing this proxy statement and the materials used in the solicitation of
proxies for the meeting will be borne by United Security Bancshares. It is
contemplated that proxies will be solicited principally through the use of the
mail, but directors, officers and employees of United Security Bancshares may solicit
proxies personally or by telephone, without receiving special compensation.

This solicitation of proxies is being made by the board of directors of
United Security Bancshares. The expense
of preparing, assembling, printing and mailing this proxy statement and the
materials used in the solicitation of proxies for the meeting will be borne by
United Security Bancshares. It is
contemplated that proxies will be solicited principally through the use of the
mail, but directors, officers and employees of United Security Bancshares may
solicit proxies personally or by telephone, without receiving special
compensation.